[U-Boot] [PATCH 2/8] net: zynq: Add clk framework support to zynq ethernet driver

Stefan.Herbrechtsmeier at weidmueller.com Stefan.Herbrechtsmeier at weidmueller.com
Wed Jan 11 08:30:50 CET 2017 

> -----Ursprüngliche Nachricht-----
> Von: Michal Simek [mailto:monstr at monstr.eu]
> Gesendet: Dienstag, 10. Januar 2017 16:23
> 
> On 10.1.2017 15:46, Stefan.Herbrechtsmeier at weidmueller.com wrote:
> >> -----Ursprüngliche Nachricht-----
> >> Von: Michal Simek [mailto:monstr at monstr.eu]
> >> Gesendet: Dienstag, 10. Januar 2017 14:59
> >> An: Herbrechtsmeier, Stefan; u-boot at lists.denx.de
> >> Cc: Herbrechtsmeier, Stefan; Albert Aribaud; Michal Simek; Joe
> >> Hershberger
> >> Betreff: Re: [PATCH 2/8] net: zynq: Add clk framework support to
> zynq
> >> ethernet driver
> >>
> >> On 4.1.2017 13:27, stefan.herbrechtsmeier at weidmueller.com wrote:
> >>> From: Stefan Herbrechtsmeier
> <stefan.herbrechtsmeier at weidmueller.de>
> >>>
> >>> If available use the clock framework to set the tx clock rate of
> the
> >>> zynq ethernet controller.
> >>>
> >>> Signed-off-by: Stefan Herbrechtsmeier
> >>> <stefan.herbrechtsmeier at weidmueller.com>
> >>> ---
> >>>
> >>>  arch/arm/include/asm/arch-zynqmp/sys_proto.h |  5 -----
> >>>  drivers/net/zynq_gem.c                       | 31
> >> ++++++++++++++++++++++++++++
> >>>  2 files changed, 31 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/arch/arm/include/asm/arch-zynqmp/sys_proto.h
> >>> b/arch/arm/include/asm/arch-zynqmp/sys_proto.h
> >>> index 1db2bd6..bd633a6 100644
> >>> --- a/arch/arm/include/asm/arch-zynqmp/sys_proto.h
> >>> +++ b/arch/arm/include/asm/arch-zynqmp/sys_proto.h
> >>> @@ -8,11 +8,6 @@
> >>>  #ifndef _ASM_ARCH_SYS_PROTO_H
> >>>  #define _ASM_ARCH_SYS_PROTO_H
> >>>
> >>> -/* Setup clk for network */
> >>> -static inline void zynq_slcr_gem_clk_setup(u32 gem_id, unsigned
> >>> long
> >>> clk_rate) -{ -}
> >>> -
> >>>  int zynq_slcr_get_mio_pin_status(const char *periph);
> >>>
> >>>  unsigned int zynqmp_get_silicon_version(void); diff --git
> >>> a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c index
> >>> 9bfb89f..9118e49 100644
> >>> --- a/drivers/net/zynq_gem.c
> >>> +++ b/drivers/net/zynq_gem.c
> >>> @@ -9,6 +9,7 @@
> >>>   * SPDX-License-Identifier:	GPL-2.0+
> >>>   */
> >>>
> >>> +#include <clk.h>
> >>>  #include <common.h>
> >>>  #include <dm.h>
> >>>  #include <net.h>
> >>> @@ -180,6 +181,9 @@ struct zynq_gem_priv {
> >>>  	struct phy_device *phydev;
> >>>  	int phy_of_handle;
> >>>  	struct mii_dev *bus;
> >>> +#if defined(CONFIG_CLK) || defined(CONFIG_SPL_CLK)
> >>> +	struct clk tx_clk;
> >>> +#endif
> >>>  };
> >>>
> >>>  static inline int mdio_wait(struct zynq_gem_regs *regs) @@ -364,6
> >>> +368,9 @@ static int zynq_gem_init(struct udevice *dev)
> >>>  	u32 i, nwconfig;
> >>>  	int ret;
> >>>  	unsigned long clk_rate = 0;
> >>> +#if defined(CONFIG_CLK) || defined(CONFIG_SPL_CLK)
> >>> +	unsigned long clk_rate_rounded;
> >>> +#endif
> >>>  	struct zynq_gem_priv *priv = dev_get_priv(dev);
> >>>  	struct zynq_gem_regs *regs = priv->iobase;
> >>>  	struct emac_bd *dummy_tx_bd = &priv->tx_bd[TX_FREE_DESC]; @@ -
> >> 466,8
> >>> +473,22 @@ static int zynq_gem_init(struct udevice *dev)
> >>>  		break;
> >>>  	}
> >>>
> >>> +#if defined(CONFIG_CLK) || defined(CONFIG_SPL_CLK)
> >>> +	clk_rate_rounded = clk_set_rate(&priv->tx_clk, clk_rate);
> >>> +	if (IS_ERR_VALUE(clk_rate_rounded)) {
> >>> +		dev_err(dev, "failed to set tx clock rate\n");
> >>> +		return clk_rate_rounded;
> >>> +	}
> >>> +
> >>> +	ret = clk_enable(&priv->tx_clk);
> >>> +	if (ret && ret != -ENOSYS) {
> >>> +		dev_err(dev, "failed to enable tx clock\n");
> >>> +		return ret;
> >>> +	}
> >>> +#else
> >>>  	zynq_slcr_gem_clk_setup((ulong)priv->iobase !=
> >>>  				ZYNQ_GEM_BASEADDR0, clk_rate);
> >>> +#endif
> >>>
> >>>  	setbits_le32(&regs->nwctrl, ZYNQ_GEM_NWCTRL_RXEN_MASK |
> >>>  					ZYNQ_GEM_NWCTRL_TXEN_MASK);
> >>> @@ -678,6 +699,9 @@ static int zynq_gem_ofdata_to_platdata(struct
> >> udevice *dev)
> >>>  	struct eth_pdata *pdata = dev_get_platdata(dev);
> >>>  	struct zynq_gem_priv *priv = dev_get_priv(dev);
> >>>  	const char *phy_mode;
> >>> +#if defined(CONFIG_CLK) || defined(CONFIG_SPL_CLK)
> >>> +	int ret;
> >>> +#endif
> >>>
> >>>  	pdata->iobase = (phys_addr_t)dev_get_addr(dev);
> >>>  	priv->iobase = (struct zynq_gem_regs *)pdata->iobase; @@ -699,6
> >>> +723,13 @@ static int zynq_gem_ofdata_to_platdata(struct udevice
> >> *dev)
> >>>  	}
> >>>  	priv->interface = pdata->phy_interface;
> >>>
> >>> +#if defined(CONFIG_CLK) || defined(CONFIG_SPL_CLK)
> >>> +	ret = clk_get_by_index(dev, 2, &priv->tx_clk);
> >>> +	if (ret < 0) {
> >>> +		dev_err(dev, "failed to get clock\n");
> >>> +		return ret;
> >>> +	}
> >>> +#endif
> >>>
> >>>  	printf("ZYNQ GEM: %lx, phyaddr %x, interface %s\n", (ulong)priv-
> >>> iobase,
> >>>  	       priv->phyaddr, phy_string_for_interface(priv->interface));
> >>>
> >>
> >> Can you please rebase it on the top of this?
> >> https://patchwork.ozlabs.org/patch/706419/
> >>
> >> The reason why this patch was written in this way is that we don't
> >> have full zynqmp clk driver yet but we are using fixed clock where
> >> you can't run set_rate which fails.
> >>
> > The patch assumes that the EMIO_ENET_TX_CLK is always fixed. Is this
> true?
> >
> > Why don't you add a set_rate() function to the fixed clock?
> 
> It would be a solution but I am not sure if fixed clock was designed
> for this. I would expect that fixed clock only provided clock which you
> can't change.

I think the current clock framework is not optimal as it doesn't abstract the clock framework from the drivers. I don't know why a not clock driver want to know that an internal clock ops isn't implemented.

I would expect that the driver should not care what clock provides the rate. The clk_set_rate() function should always return the nearest possible clock rate and the clk_enable() shouldn't failed with a missing ops function. Otherwise this functions should be mandatory.

> It means we need to have something as transition when u-
> boot has real clk driver for zynqmp.

We could use the same fall back for the clk_set_rate() as we use for the clk_enable() and ignore the -ENOSYS error.

> >
> > Additionally the patch is missing an enable function call.
> 
> correct.
> 
> >
> > I don't think the emio configuration should be keep in the Ethernet
> driver as it is part of the clock configuration and doesn't influent
> the network interface.
> 
> Please correct me if I am wrong. Are you saying that with these patches
> especially 8/8 clock for emio will handled automatically?

What do you mean by 8/8 clock?

The Ethernet driver should not care how the clock is connected and only set the required clock rate. The clock driver should route the function calls to the correct clock.

Regards,
  Stefan



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